Surface flotation system



Aug. 22, 1961 L. E. WEDDING 2,996,986

SURFACE FLOTATION SYSTEM Filed Dec. 8, 1952 2 Sheets-Sheet 1 FlG.l

INVENTOR LEON E. WEDDING ATTORNEYS Aug. 22, 1961 L. E. WEDDING SURFACE FLOTATION SYSTEM 2 Sheets-Sheet 2 Filed Dec. 8, 1952 FIG. 4

INVENTOR LEON E. WEDDING ATTORNEYS United tates 2,96,986 Patented Aug. 22, 1961 See 2,996,986 SURFACE FLOTATION SYSTEM Leon E. Wedding, 3813 17th St. NE, Washington, DJC. Filed Dec. 8, 1952, Ser. No. 324,860 4 Claims. (Cl. 102-14) (Granted under Title 35, U5. Code (1952), see. 266) The invention herein described may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

The present invention relates to an underwater suspension system and more particularly to a buoyancy system adapted to maintain itself on the surface of the water.

In modern warfare it is frequently desirable to position equipment in the water and to launch such equipment from either surface ships or from a submerged submarine. In launching a buoyancy system from a depth of several hundred feet in water, the buoyancy system is subjected to very high pressure which may cause improper operation or destroy the device entirely, and since it is usually desired to position the equipment on the surface of the water, a system must operate to elevate the equipment to the surface. It is impractical to employ a rigid tank for buoyancy purposes because of its size and weight, so that the non-rigid structure is required which can successfully operate at water pressures of several hundred pounds per square inch. It is also necessary that the equipment remove itself after its useful life is expended.

The device herein described may be launched from any depth up to 400 feet of water and may be launched from the flare tube of a submarine. The buoyancy system is vented to sea, thus equalizing the pressures inside and outside the non-rigid buoyancy tank, so that flexible impervious material may be employed therefor. The equipment to be supported has a constant weight and a gas generator having a substantially constant generating rate is employed to replenish the gas in the buoyancy tank or balloon as it is called herein. A cap having an orifice therein is secured to the top of the balloon for controlling the period of time that the device will be operative.

It is an object of the present invention to provide a buoyancy system having a self-inflating balloon.

It is another object of the present invention to provide a buoyancy system having a self-inflating balloon with a control orifice valve for controlling the rate of gas discharged from the balloon.

Further objects together with the attendant advantages of the present invention will be made apparent to those skilled in the art by reference to the following description in connect-ion with the appended drawings in which:

FIG. 1 is a perspective view with parts partially broken away showing the organization of elements in the device;

FIG. 2 is an elevation view partially in section of the buoyancy system of the present invention taken on lines 2-2 of FIG. 1;

FIG. 3 is a perspective view showing the device in an assembled condition;

FIG. 4 is a detailed view taken on lines 4-4 of FIG. 3; and

FIG. 5 is a cross-sectional view of the assembled device taken on lines 55 of FIG. 3.

Referring now to the drawings in which the same or corresponding parts are identified by like numbers, there is shown an envelope or balloon l1 constructed of flexible impervious material. The material employed is preferably not resilient, so as to prevent changes in the volume of the balloon itself, although plastic and similar material may be employed if desired. A suitable material for the construction of the balloon 11 is rubberized fabric,

since it may be readily folded into a small space and stored for extended periods of time. The balloon may be of any desired shape, but is illustrated herein as cylindrical with rounded ends. Couplings 15 and 17' are sealed into the upper and lower ends of the balloon for purposes later to be described. A gas generator 33 is secured to the underside of balloon 11 for providing gas thereto in order to inflate the balloon. Any type of equipment 13, such as that used for military purposes, is adapted to be suspended from the gas generator by means of a cable 88, as hereinafter described.

The gas generator employed with the present invention may be of any desired type, the major requirements being that it be light weight and provide a substantially constant emission of gas over a considerable period of time. Because the weight of any gas is negligible with respect to the weight of water, the type of gas employed is unimportant. The gas generator herein described is inexpensive to construct, rugged, and capable of producing a substantially constant flow of gas at high pressures, although many other types of generators may also be employed if desired.

As best seen in FIG. 2, the gas generator 33 com prises an outer cup 35 and a vent tube 37 extending through the bottom of the cup to a point near the top of the cup. The cup is adapted to be sealed to the coupling 17 in the bottom of the balloon 11, and the volume between the inside of the cup- 35 and the vent tube 37 is filled to within about one-half inch of the top of the vent tube with a chemical 39 which liberates a gas upon contact with water. Suitable chemicals include lithium hydride, calcium hydride, lithium metal, and others. In the present disclosure and for the purposes of illustration, lithium hydride is employed, since it liberates approximately thirty-five cubic feet of hydrogen at atmospheric pressure per pound of chemical and is capable of creating very high pressures.

The rate at which gas is generated depends in a large measure upon the effective area of chemical exposed to the water. Thus the area of the surface of the chemical and the extent to which the chemical is compacted into its holder affect the rate of generation, and the addition of wax to the chemical will greatly retard its emission of gas. In the present generator, lithium hydride without wax is compacted with a pressure of about four tons per square inch of surface area.

Water entering the gas generator 33 through the vent tube 37 flows on to the lithium hydride, and immediately sets up a chemical reaction liberating hydrogen gas. The hydrogen gas liberated on the concavity between the cup 35 and the vent tube 37 forms a gas pocket which forces the major portion of the water away from the chemical 39 until the remaining water is exhausted in the reaction. The gas generator thus allows the lithium hydride to re ceive only a small quantity of water at any one time with which to react and the generation rate is thereby maintained substantially constant.

Gas liberated by the generator 33 rises through the water into the balloon 11 creating a pressure therein which forces Water from the balloon through the vent tube 37 to increase the buoyancy of the system. It will be noted that the pressure within the balloon 11 is equal to the pressure on the outside, so that substantially no pressure is exerted on the impervious material. A vent is provided at the top of the balloon 11 and it may be of any design capable of venting the gas at a predetermined rate. In the particular embodiment shown herein, a cap 41 is secured to the top of the balloon and comprises an ordinary auto tire valve cap having an orifice therein of a predetermined size, the size of this orifice being determined by the rate at which it is desired to allow gas to escape from the balloon. When the chemical has been completely expended, gas is no longer generated and as soon as the gas remaining within balloon 11 has escaped through the cap 41, the volume of gas within the balloon commences to contract and the whole unit assumes negative buoyancy and sinks to the bottom.

It is necessary at great depths that the balloon 11 be inflated immediately, even though the required replenishment rate of the gas generator is small. In order to provide an immediate supply of gas, lithium hydride crystals are placed within the folds of the balloon 11 when it is assembled. Water entering the balloon in launching reacts with the chemicals to generate a considerable volume of gas which opens the balloon at once and provides a high positive buoyancy to cause the unit to rise rapidly. This feature is indicated in FIG. by the reference character 43. An excess quantity of lithium hydride within the balloon is used to insure that the balloon will be completely filled under all launching conditions, since any excess gas will be discharged through the vent tube 37 without danger to the apparatus.

In order to launch the buoyancy system and its attached load from a submarine at a depth of several hundred feet, the entire assembly is packed in a cylindrical container 65 as shown in FIG. 3. In the present device the cylindrical container 65 has a diameter of about three inches, varying in length and comprises an upper compartment 67 containing the packed buoyancy system and a lower compartment 69 containing the equipment to be suspended from the balloon. The two compartments are joined together by a water-tight joint at the juncture 71. As best shown in FIG. 4, the lower compartment 69- is provided with a neck 73 having a reduced diameter adapted to extend to within the end of the upper compartment 67. The exterior of the neck 73 is provided on its exterior with a groove 75 adapted to receive the O-ring 77 of natural or synthetic material, and the end 79 of the upper compartment 67 is crimped over the O-ring 77. It will be apparent that the upper compartment 67 is securely fastened to the lower compartment under conditions of ordinary handling but may be separated by an axial force.

The buoyancy system of the present invention is packed into the upper compartment 67 as shown in FIG. 5. An

explosive charge 81 is located in the upper end of the upper compartment 67 which upon detonation acts upon the disc 83- to force the two sections of the container apart to eject the buoyancy system from the upper compartment. In order to insure that the container 65 is clear of the launching structure before explosive charge 81 is detonated, a delayed action detonator 85 is used. The system for actuating the detonator 85 varies with the application in which the apparatus is used, and is not a part of this invention so that extensive explanation is not required. The detonator 85 is actuated upon launching of the container, and supplies a delay of about four seconds.

In order to prevent the force of the explosion from damaging the balloon 11 arcuate segments 87 are placed around the buoyancy system to transmit the thrust to the lower compartment 69. The arcuate segments 87 are maintained in place around the buoyancy system by the inner surface of the upper compartment 67, and drop off when the buoyancy system is ejected therefrom.

The lower compartment 69 of the container 65 houses the equipment to be supported by the buoyancy system and is attached to the buoyancy system by means of rope 88. The rope 88 may be made of any substance which is relatively free from tendencies to kink or tangle and as used herein is sash cord. The attachment of the rope to the buoyancy system and the lower compartment 69 may take any desired form and is illustrated herein as rings 90 and 92 attached to the gas generator 33 and the lower compartment 69 respectively.

For most applications, it -is desirable to provide electrical power to operate such apparatus as is to be used .4 in the lower compartment 69, and for this reason, sea water batteries 89 are attached to the upper end of the lower compartment. Such batteries, as is well known to those skilled in the art, produce a potential when immersed in sea water and are inactive until so immersed. When equipped with such batteries the apparatus is inactive until launched. In operation, the container 65 is ejected from a suitable launching device, and in being so ejected, actuates the delayed action detonator 85. After the time delay of the detonator, the explosive charge 81 is detonated, which separates the two compartments of the container -65 and ejects the buoyancy system from the upper compartment 67.

When the buoyancy system is ejected into the water, water enters the gas generator 33 and the balloon 11, where it comes in contact with the lithium hydride, and immediately liberates hydrogen in a large volume. The hydrogen thus liberated inflates the balloon, creating a positive buoyancy which causes the balloon to rise to the surface. As the balloon rises the pressure of the water surrounding it decreases in proportion to the depth, and the gas within the balloon expands accordingly, excess gas escaping from the vent tube 37.

As afore-mentioned, the gas will be continually vented to the atmosphere as long as any such gas is being generated by the reaction of lithium hydride with the water. When the gas is expended, the unit sinks to the bottom, thus automatically removing itself at the end of its useful life.

It will be readily apparent to those skilled in the art that only a preferred modification has been described herein, and that many changes therein are possible without departing from the spirit of the present invention. It should be understood, of course, that it is intended to cover all changes and modifications of the example of the invention herein chosen for the purposes of the disclosure, which do not constitute departures from the spirit and scope as set forth in the appended claims.

What is claimed is:

1. In combination, a buoyancy system comprising a flexible impervious envelope, an orifice in the top of said envelope, a gas generator, chemical means respectively positioned in each of said envelope and generator for generating a gas when placed in contact with water, and connecting means securing said gas generator externally to said envelope, whereby said buoyancy system is made buoyant by the gas directed from said generator into said envelope.

2. In combination, a buoyancy system comprising a flexible impervious envelope, a gas generator externally affixed to said envelope, a first chemical substance and a second chemical substance respectively positioned in each of said envelope and generator for generating a gas when the chemical substances come in contact with water, a suspended load having negative buoyancy, a cable, means connecting said cable at one end to said suspended load and at the other end to said generator, and an orifice in said envelope whereby the rate of gas flow from said envelope is controlled by the size of said orifice.

3. The combination according to claim 2 wherein said chemicals comprise lithium hydride.

4. The combination according to claim 2 wherein said gas generator comprises an outer cup'detachably connected to said envelope, a vent tube extending through the bottom of said cup to a point adjacent the top thereof, and means connecting the top of said outer cup with the bottom of said envelope.

References Cited in the file of this patent UNITED STATES PATENTS 1,442,345 Kee Jan. 16, 1923 2,642,693 Broady June 23, 1953 FOREIGN PATENTS 38,603 Sweden Mar. 24, 1915 

